viii PREFACE Bay and of explorations in Alaska by members of the National Geographic Society; C. A. Stockton's 1 and J. C. CantweU's2 descriptions of ground ice in Arctic Alaska; C. L. Andrews' study of Muir Glacier in 1902, the first after the great earthquakes of 1899;3 Fremont Morse's description of the same in 1907;4 W. C. Mendenhall's descriptions of the glaciers in the Wrangell Mountains;8 W. A. Dickey's discovery and np.im'ng of Mt. McKinley with its glaciers;8 Robert Muldrow's determination of its height and the position of more glaciers;7 A. H. Brooks' plan of climbing Mt. McKinley, with mapping of still more of the glaciers;8 Ferdinand Westdahl's photographs of the glaciers and snowfields on the volcanoes of Unimak Island in the Aleutians;9 W. H. Osgood's description of the glaciers near Lake Clark;10 G. K. Gilbert's summary of the glaciers of Alaska;11 and many other papers12 dealing incidentally with glaciers and glaciation in Alaska. The National Geographic Society's Alaskan expedition of 1909, the plan of which was announced in the Magazine for June, 1909, was under charge of the authors of this volume, the other members of the party being W. B. Lewis of the U. S. Geological Survey, the topographer; Oscar von Engeln of Cornell University, who took and developed many of the photographs ;E. F. Bean of the University of Wisconsin, who acted as rodman and general assistant; A. R. Campbell of the University of Washington, who ran the launch; Charles Johnson of Yakutat, who was boatman and camp hand; and a Japanese boy, as cook. The Society's 1910 expedition was under the leadership of the junior author, assisted by Messrs. Lewis and Bean of the 1909 party, F. E. Williams of the University of Wisconsin, rodman; R. G. Byers and E. A. Conner of the University of Washington, photographer and boat engineer respectively; and a cook. The Society's 1911 expedition, under the direction of both authors of this volume, devoted most of the season to glacier study in other parts of Alaska than are described in this volume. The junior author, however, gave two weeks to additional observations of the Prince William Sound and Copper River glaciers before he was joined by the senior author and Russell S. Tarr. The junior author also visited Yakutat Bay in 1918. Each of the authors had previously spent two summers in Alaska, the senior author in Yakutat Bay in 1905 and 1906, the junior author in Controller Bay, Prince William Sound, Cook Inlet, and Alaska Peninsula in 1904, and in Yakutat Bay in 1905. Both of these previous seasons of field work in Alaska by the senior author were supported by the U. S. Geological Survey. The 1904 season by the junior author was in a U. S. Geological Survey party, but in 1905 he was supported by a grant of money from the American Geographical Society of New York. 1 Nat. Geog. Mag., Vol. n, 1890, pp. 178-179. * Ibid., Vol. VH, 1896, pp. 345-346. 3 Ibid., Vol. XIV, 1903, pp. 441-446. •Ibid., Vol. XIX, 1908, pp. 76-78. • Ibid., Vol. XIV, 1903, pp. 395-407. 8 Ibid., Vol. Vm, 1897, pp. 322-327. 1 Ibid., Vol. XH, 1901, pp. 812-813. 8 Ibid., Vol. XIV, 1908, pp. 80-85. 8 Ibid., Vol. XIV, 1903, pp. 93, 94, 97, 98. " Ibid., Vol. XV, 1904, p. 328. 11 Ibid., Vol. XV, 1904, pp. 449-450. »Ibid., Vol. XX, 1909, pp. 585-623; Vol. XXTT, 1911, pp. 597-600, 786; Vol. TnTTTT, 1912, pp. 428-429, 684-713.